Pope Benedict XVI decried the increasing commercialisation of Christmas as he celebrated Christmas Eve Mass, urging the faithful to look beyond the holiday's "superficial glitter" to discover its true meaning.

Pope Benedict XVI decried the increasing commercialisation of Christmas as he celebrated Christmas Eve Mass, urging the faithful to look beyond the holiday's "superficial glitter" to discover its true meaning.

Benedict presided over the service in a packed St Peter's Basilica, kicking off an intense two-week of Christmas-related public appearances that will test the 84-year-old pontiff's stamina amid signs that fatigue is starting to slow him down.

The Christmas Eve Mass was moved up to 10 pm from midnight several years ago to spare the pope a late night that is followed by an important Christmas Day speech.

In a new concession this year, Benedict processed down the basilica's central aisle on a moving platform to spare him the long walk.

Benedict appeared to hold up well during the Mass despite the late hour and a dry cough that interrupted his homily.

In his homily, Benedict lamented that Christmas has become an increasingly commercial celebration that obscures the simplicity of the message of Christ's birth.

"Let us ask the Lord to help us see through the superficial glitter of this season, and to discover behind it the child in the stable in Bethlehem, so as to find true joy and true light," he said.

It was the second time in as many days that Benedict has pointed to the need to rediscover faith to confront the problems facing the world today.

In his end-of-year meeting with Vatican officials on Thursday, Benedict said Europe's financial crisis was largely "based on the ethical crisis looming over the Old Continent."

Benedict officially kicked off Christmas a few hours before the evening Mass, lighting a candle in his studio window overlooking St Peter's Square in a sign of peace, as crowds gathered to witness the unveiling of the Vatican's larger-than-life sized nativity scene.